Papers by Author: Yi Wei

Abstract: Photocatalytic paint was prepared by adding Fe-doped TiO2 nanocrystalline powders into self-engineered oxidation-resistant latex paint system. The UV-Vis diffuse reflectance spectroscopy was used to characterize the light absorption properties of the paint. The colony counting method was used to study photocatalytic sterilization ratio of E. coli under visible light irradiation. Effects of the kinds and amounts of TiO2 powders added in the paint on the sterilization ratio under visible light irradiation with fixed relative humidity were systematically investigated. The UV-Vis diffuse reflectance spectroscopy indicates that the absorption thresholds of the Fe-doped TiO2 paint have red-shifted into visible light region. The antibacterial experiment results show that the sterilization ratio of E. coli can exceed more than 99% in less than 4 hours under 400-lux-visible light irradiation under RH of 55%.

Abstract: Using TiOSO4 as precursor, Fe(NO3)3⋅9H2O as the source of Fe, CN3H5⋅HCl as the source of N, Fe/N co-doped TiO2 powder has been prepared by hydrothermal method. The as-prepared powders were characterized by XRD, BET, TEM and UV-Vis spectrophotometer. The nanocrystalline Fe/N Co-doped TiO2 powders are composed of anatase and show light-yellow in color. The grain size is about 11.1nm and the specific surface area is 145m2/g. XPS results show that N atoms and Fe atoms were incorporated into the lattice of TiO2 and the concentration of N and Fe doped in TiO2 was 0.8at% and 2.2at%, respectively. The UV-Vis diffuse reflection spectra indicate that the absorption edges of the co-doped TiO2 powders has well red-shifted into visible light region up to 606nm. The Fe/N co-doped TiO2 exhibits excellent photocatalytic activity by sterilizing E. coli completely within 1 hour under visible light irradiation.

Abstract: Nitrogen-doped TiO2 has been prepared by calcining technical grade guanidine hydrochloride and commercial anatase TiO2 powders. XRD patterns indicate that the prepared powders are composed of anatase. XPS results show that N atoms have been incorporated into the lattice of anatase. UV-Vis reflectance spectra show that the light absorption of the synthesized N-doped anatase powders has red-shifted well into visible-light region. Degradation of methylene blue (MB) aqueous solution by N-doped anatase has been investigated by UV-Vis light spectrophotometer. The 400-mL 10 mg/L aqueous solution of MB could be degraded with 4 g N-doped TiO2 within 4.5 hrs of visible light irradiation. Photocatalytic paint was prepared by adding the synthesized N-doped nanocrystalline anatase TiO2 powders into self-engineered oxidation resistance latex paint system. The effects of the amount and types of the TiO2 in the paints on the sterilization were systematically investigated. The colony counting method was used to study its sterilization performance under visible light irradiation. The sterilization experiments show that the rate of sterilizing E. coli by the N-doped TiO2 modified paint can exceed more than 99% after irradiation by the visible light for 2 to 4 hours.